A Novel Hybrid Strategy for Detecting COD in Surface Water
| Autor: | Yankai Wang, Qiaoling Du, Guiping Zhang, Xinpo Lu |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Accuracy and precision
Materials science turbidity compensation 02 engineering and technology COD Interference (wave propagation) 01 natural sciences lcsh:Technology Absorbance lcsh:Chemistry Partial least squares regression partial least squares permutation entropy General Materials Science Turbidity Extreme value theory Instrumentation lcsh:QH301-705.5 Fluid Flow and Transfer Processes lcsh:T Process Chemistry and Technology 010401 analytical chemistry Chemical oxygen demand General Engineering 021001 nanoscience & nanotechnology lcsh:QC1-999 0104 chemical sciences Computer Science Applications Wavelength lcsh:Biology (General) lcsh:QD1-999 lcsh:TA1-2040 first derivative 0210 nano-technology Biological system lcsh:Engineering (General). Civil engineering (General) lcsh:Physics |
| Zdroj: | Applied Sciences, Vol 10, Iss 8801, p 8801 (2020) Applied Sciences Volume 10 Issue 24 |
| ISSN: | 2076-3417 |
| Popis: | The prediction of chemical oxygen demand (COD) by ultraviolet–visible absorption spectrum is a common method. Many researchers use the absorbance at the characteristic wavelength to establish COD prediction models. However, selecting the characteristic wavelength is a problem. In this paper, the extreme values of absorption spectrum change rate, was proposed as a new characteristic parameter to determine the characteristic wavelengths. On this basis, a novel hybrid strategy for detecting COD in surface water was proposed. We first proposed to combine the first derivative method with the permutation entropy method (FDPE) to determine the characteristic wavelengths. Then we used partial least square (PLS) to establish a COD prediction model. Experimental results demonstrated the linear correlation coefficient (R2) of the FDPE_PLS was above 0.99 without turbidity interference. Secondly, a dual-wavelength method (DWM) was proposed to determine the turbidity values. The DWM used slopes of absorbance values at 400 nm and 600 nm to predict the turbidity values. Compared with the single-wavelength method, the DWM improves the measurement accuracy of turbidity. Finally, a new turbidity compensation method was proposed to compensate for the interference in the first derivative spectrum. After compensation, FDPE_PLS can predict COD concentrations accurately, whose R2 was 0.99. |
| Databáze: | OpenAIRE |
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